You are not alone.Originally Posted by MetroidZ
Edit: Also... the Sonic Rush 3D stage was just the rip from Sonic 2 put into a 3D environment, it's still on a 2D control pane, just with the DS touchscreen (which was a nice add-on though). Sonic Rush has 3D models, but is essentially a 2D game, meaning moving on x and y axis', not z.
As for Sonic CD, that was an advanced version of Sonic 3's special stage (though I could be wrong, Sonic CD might've been out before Sonic 3). While it was good, and still is, it was a 3D-tidbit added onto the game. The whole game itself rocked as 2D, and will always rock as 2D.